new to iphone, quick ? before makin my purchase

Hi. Getting ready to make the plunge into getting an iPhone.. looking at BestBuy since they have em for 99.99 right now. Anyhow, went today to look, and almost got one, til I got to the part about asking what happens if I canel later down the road (ie: I move, and coverage stinks, etc).

Guy told me I'd be liable for the pro-rated ETF (fine, no issue with that), AND that I'd have to return the phone TO Best Buy, or they'd bill me the difference (400.00 or so) of the retail vs 2 year price. I asked him again to confirm what he said, and he told me I'd be billed. He said my final ATT bill would say either to return the phone to THEM (ATT), or to Best Buy.

I called ATT and asked them, and they said they don't require the phone to be returned, so I dunno if this is some BB BS, or if the guy don't know what he's saying.

I called another BB and asked the mobile rep there, and they told me that the first BB was rep was full of it... so.. before I make the plunge, does anyone happent to know how this would work out?

I dont see how BB could bill me anything, especially if I paid with cash, and none of the paperwork BB wanted me to sign said that if you cancelled it had to be returned to them or you'd be billed. Any help would be appreciated.